Load interrupter housed fuse cutouts with tube drop-out



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LOAD INTERRUPTER HOUSED FUSE CUTOUTS WITH TUBE DROP-OUT .d RU PM @C my a e d 6 Sept. 6, 1960 Filed Feb. s, 1959 Sept. 6, 1960 G. R. MCcLoUD- LOAD INTERRUPTER HOUSED FUSE CUTOUTS WITH TUBE DROP-OUT Filed Feb.` 3, 1959- 2 Sheets-Sheet 2 .d f mw m T 7 5T We t 1W n@ e MJ w 6W United States Patent LOAD INTERRUPTER HOUSED FUSE CUTOUTS WITH TUBE DROP-OUT George R. McCloud, South Milwaukee, Wis., assignor to McGraw-Edison Company, Milwaukee, Wis., a corporation of Delaware Filed Feb. 3, 1959, Ser. No. 790,852 8 Claims. (Cl. 200-114) out tube indicating means associated therewith.

The usual practice is to provide in an electric system, a fuse for interrupting a circuit under overload conditions and in series therewith a circuit breaker which may be manually operated to open the circuit operating under normal load conditions.

Theoretically, the fuse can be used as a circuit breaker. However, the fuse contacts are not designed to withstand the destructive effects of arcing when the contacts are separated under load.

The principal object of this invention is to provide a fuse cutout having a fuse link which will interrupt a circuit under overload conditions and includes manually operable means for breaking the fuse link when it is desirable to interrupt the circuit under normal loads thus `dispensing with the use of a circuit breaker in series with the fuse cutout and permitting the operation of the fuse cutout to open circuit position without producing injurious arcing beween the fuse contacts. In conjunction with the above object, it is to be particularly noted that the invention also provides a link break mechanism together with a so called time delay tlipout means associated with a drop down or indicating mechanism whereby the fuse tube or other suitable means may be dropped down or placed in indicating position responsive to an overload condition such as thermal rupture of the fuse link from fault current. A drop down tube is important where cutouts may remain unfused for appreciable periods of time after the link has blown since it prevents tracking of the organic tube material.

A further object of this invention is to provide a housed fuse cutout having mechnical means for breaking a fuse link which may be selectively actuated and thus the housed cutout may be opened either after or without breaking the fuse link.

A futher object of this invention is to provide a housed fuse cutout having link break means associated therewith which may be actuated by a separate portable tool or the like.

The novel features which are characteristic of the invention are set forth with particularity in the appended claims. The invention itself, both as to its organization and its method of operation together with additional objects and advantages thereof will best be understood by the following description of a specific embodiment when read in connection with the accompanying drawings in which:

Fig. l `is a side view, a portion of which is in section showing the inventive concepts;

Fig. la is a perspective view of a portable tool adapted to actuate the link break means;

Fig. 2 is a front elevational view of the device shown in Fig. 1; and

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Figs. 3 and 4 are semidiagrammatic views showing the operation of a link break mechanism shown in Figs. l and 2.

Returning to Fig. l of the drawings, the housed fuse cutout comprises a porcelain housing H having an open front and bottom and a door D made of insulating material for closing the open front. The housing H has a top 15, back portion 16 and side portions 17 and 18 which define the aforementioned open front and bottom. It is to be noted that in some designs the top 15 of the housed cutout may be left open (not shown) to provide a double venting, if that function is desired. Mounted in the rear Wall 16 of the housing, and facing outwardly thereof, intermediate the top and bottom, is a hanger 19 by which the cutout is conveniently mounted to a crossarm or the like.

`Conventional upper and lower terminal means for incoming and outgoing conductors (not shown) are provided having upper side contacts 25 and lower side contacts 28 respectively for releasable engagement with a bridging fuse tube 34 assembled therein in the conventional manner. A `doubled leaf spring upper contact 26 imposes a downward force upon a metallic fuse cap 35 of fuse tube 34 to bias the tube toward an indicating position as shall become apparent.

A fusible rupturable link element 37 is disposed within the fuse tube 34 and is securely mounted to a lower contact sleeve 32 by means of thumb mounting screw 38. The link 37 retains the tube in the position shown in Fig. 1 against the bias of gravity and spring contact 26.

The lower contact sleeve 32 is firmly and lixedly mounted to the door D. Contact sleeve 32 is irregular in shape having an upper portion 32a which is generally cylindrical and adapted to surround `and provide a guide for the fuse tube 34. The bore of cylindrical portion 32a is larger than the main portion of the fuse tube 34 but smaller than the upper portion of the fuse cap 35a. Thus, the cap portion 35a provides a stop to prevent the fuse tube 34 from dropping completely through the contact sleeve 32 when the link ruptures allowing the tube to move to the dotted indicating position shown in Fig. 1.

The entire closure .assembly 30 comprising the door D, contact sleeve 32 `and fuse tube 34 are rotatably mounted on trunnion means 31 which are provided on the lower side Walls 17 and 18 of the housing H. As shown, the door D is formed with a pull ring 39 at the upper extremity thereof `for opening the door about the trunnions in a conventional manner. A pair of transverse mounting pins 29 which extend from the side walls of the contact sleeve 32 detachably lit into said trunnions 31 for locating the entire `door assembly 30 and tuse tube 34 relative to the contacts 25, 26, 28 in accordance with established conventional design. The pins 29 are mounted in the side walls of the contact sleeve 32 in axial alignment with the fuse tube 34 yand spaced upwardly from the 4bot-tom of the fuse tube a short distance and extend transversely therefrom a sufficient distance for engagement with apertures 1in the trunnions 31 Suitable retaining rings 29a are formed near the outer edge portion tof pins 29 to prevent lateral sliding of the .door relative to the housing H and trunnions 31, as best shown in Fig. 2 of the drawings. It will also be noted that the door D is formed with a necked down portion 39a at the lower end thereof, the necked down portion 39a -having a dimension less than the `distance between the :two retaining rings 29a and trunnions 31 so .as to leave room 'for yaccess of :a portable tool 57 as shall be explained.

Combination time delay, link break and flipout lever means 45 is mounted interiorly of the contact sleeve 32 at the lower end thereof. As best shown in Fig. l, the

means 45 is formed with a pivotally mounted arc segment member 40 having a cam surface 44 which provides the dual function of a time delay in the drop down of the .tube and the flipping out of the tail 37 of the fuse link afteri-t is ruptured. A spring 40g biases member 4l)` downwardly as shown in Fig. 1.

The surface 44 of tlipout lever 40 is adapted to engage a transverse roller 43 which is located in small, horizontal .slots 41 foi'med in the side walls of contact sleeve 32. Roller 43, in turn, is `adapted to engage and hold a chamfered retaining ring 36 which is iixedly mounted to the fuse tube 34 in .the position shown in Fig. 1 of the drawings until cam surface 44 has completely cleared the rol-ler 43. When cam surface 44 clearsroller 43, the roller shifts to the lefty in slot 4l as fviewed in Fig.' l, and allows retaining ring-36 to dr-op down to the dotted position shown in Fig. 1 of the drawings under the bias of gravity and spring contact 26. This is in accordance with the teachings set `forth in my co-pending application having Serial No. 726,787, tiled April 7, 1958, entitled Dropout Fuse Construction, and assigned to the assignee of the instant invention, now United States Patent 2,884,500, issued April 28, 1959.

To mechanically rupture the fuse link 37 of ilipout lever 40 is modified 'by placing a transverse cross bar 46 `at the lower extremity thereof of such a dimension that it extends sufficiently for engagement with a cam surface 53 of the load break tool 57 when the latter is mounted on pins 29. Thus, bar 46 must be of greater dimension than the necked down portion 30a of door D and less than the distance between trunnions 31.

The operation of the link break mechanism is exceedingly simple in that all it requires is that the link break .tool 57 (shown in IFig. 1.a) be inserted so that apertures 59 be hooked over mounting pins 29 :for engagement of surface 58 with link break bar 46 and the handle of the .tool 57 be rotated to exert a downward pressure upon the bar 46 and, hence, the fuse link tail 37 causing same to be ruptured. ThisY is quite well schematically shown in Figs. 3 and 4 of the drawings. Referring back to Fig. 1, it will be seen that thetube 34 is held stationary during the first part of the downward movement of lever 40 by roller 43 and the stopV 36 :on the fuse tube, thus `assuringthat link 37 will break prior to .the tube dropping down to the indicating position.

It is thus apparent that an exceedingly simple, rugged, link break mechanism is added in the housed fuse cutout with a modification of existing housed cutouts while affording lthe function of drop down tube or other indicating means to indicate that .the device has been thermallyactuated in normal eld use.

Although =a specific embodiment of the invention has been shown and described, it is with full awareness that many modifications thereof are possible. The invention, therefore, is not to be restricted except 4as insofar as is necessitated by the prior art and by the spirit of the appended claims.

What is claimed as the invention is:

1. A housed fuse cutout comprising a housing having a back portion and a pair of side portions :leaving the bottom randfront of the said housing exposed, first and second electrical contact means disposed within said housing, mounting means provided in said side por-tions of said housing, closure means pivotally mounted on .said mounting means for closing said front of said housing, said closure means comprising door means having a contact sleeve xed thereto with -a pair of pins coactuable with said mounting means, fuse means disposed on said door means for electrically bridging said lirst and second contact means and including fuse tube means disposed in an operative position and biased toward an indicating position, mechanically rupturable fuse link means disposed within said fuse tube means retaining said .fuse tube in said operative position against its bias,l

:annular retaining means tixedly disposed on said fuse tube means, and combination time delay, llipout lever, and link :break means operatively associated with both said retaining means on said Afuse tube and with said fuse link means and comprising `an arc segment member mounted on said contact sleeve, said arc segment member being disposed and held in a irst position by said fuse link means and biased to a second position `and formed with a transverse load receiving fuse link engaging portion, roller means co-actable with said arc segment member, contact sleeve, 4and retaining means on said fuse tube when said arc segment member is in said yfirst posi-tion and disengaging trom said arc segment member and retaining means when said arc segment member is in said second position, lever means co-actable with said transverse load receiving fuse linkengaging portion of said arc segment member `and operable therethrough to mechanically stress and rupture said fuse link so that actuation of said lever means affords movement of said arc segment member to its second position and disengagement of said roller means from said retaining means to afford movement of sa-id fuse tube to an indicating position.

2. A housed fuse cutout comprising, in combination, Ia casing having upper and lower stationary contacts disposed therein, la door for said casing, interengaging trunnion and bearing means between said casing-and said door for releasably pivoting said door on said casing, a fuse tube mounted on said door and having `an upper contact and-a lower contact and having an open lower end, a mechanically rupturable fuse link within said fuse tube electrically join-ing the upper and lower contacts of the fuse tube and projecting outwardly from the lower end of said fuse tube, a llipout lever pivotally mounted on said door and engaging said fuse link, said llipout lever being spring-biased 4toward flipout motion to withdraw any remaining portion .of .said fuse.. link lfrom said fuse tube upon rupture of said fuse link and being restrained against flipout motion by said fuse li-nk, a portion of .said door being spaced from said casing to permit insertion of a tool into the interior of said casing, and fuse link rupturing means including a tool engagingsurface on said ilipout lever so spaced from the point of engagement of said lever with said fuse link that a force exerted against said surface urges saidlever tow-ard ipout motion and also so spaced from said trunnion means to permit rupture of said fuse link by said tool operated as a lever fulcrumed about said trunnion means and bearing against said surface, said fuse tube being movable relative to said door and biased toward a dropout position wherein it is visible from the exterior of said housing, .and means for normally holding said fuse tube in a position wherein the upper and lower contacts thereof engage said upper and lower stationary contacts respectively and being responsive toA flipout motion of said lever to permit movement -of said fuse tube to said dropout position.

3. A housed fuse cutout comprising, in combination, a housing, iirst and second electrical terminals within said housing, a .door for said housing, interenga-ging trunnion land bearing means between said housing and said door for releasably pivoting said door on said housing, fuse means affixed to said door for electrically bridging said iii-st and second terminals .when said door is closed and including a fuse tube and a mechanically rupturable fuse link within said fuse tube, a portion of said door being spaced from said housing to permit insertion of a tool into the interior of said housing, a flipout lever pivotally mounted on said door and engaging said fuse link, and link break means mounted on said door including .a tool engaging surface on saidlever so spaced from the point of engagement of said lever with said fuse link that a torce exerted against said surface urges said lever toward iiipout motion and in a direction -to rupture said fuse link .andalso .spaced from said trunnion means to perm-it breaking of said fuselink by said tool used as a lever fulcrumed about said trunnion means and bearing against said surface.

4. A drop-out fuse construction comprising a casing having upper and lower stationary contacts disposed therein Iand a door pivotally mounted thereon, a fuse tube slidably carried by said door and having an upper contact normally engaging the upper stationary contact and having a lower contact, a fuse link within said fuse tube electrically connecting the upper contact of said fuse tube with Ithe lower stationary contact when said door is closed, a ipout lever engaging said fuse link and pivotally mounted on said door within said housing and normally held by said fuse link in -a biased position tending to withdraw any remain-ing portion of said fuse link upon rupture of said fuse link, said fuse ltube having projecting means adjacent its lower end, guided means normally engaging said projecting means on said fuse tube, said flipout lever having a cam portion normally engaging said guided means and restraining said fuse tube to provide a ltime delay, a portion of said door being spaced from said casing 4to permit insertion of a tool into the interior of said casing, said door carrying transverse pin means for fulcrumingsaid tool and said iiipout lever having a surface spaced yfrom said fulcrum pin means 4and adapted to engage said .tool inserted within said casing to permit mechanical rupture of said fuse link by lever action.

5. A housed fuse cutout comprising, in combination, a housing, first and second electrical terminals within said housing, a door pivotally mounted on said housing, fuse means mounted on said door including a fuse tube movable relative to said door to a drop-out position wherein it is visible from the :exterior of said housing and a mechanically rupturable fuse link within said fuse tube, means for normally holding said fuse tube in an operative position wherein said fuse means electrically bridges said first and second terminals when said door is closed and being responsive to rupture of said fuse link to release said fuse tube and permit movement lthereof to said ldrop-out position, a portion of said door being spaced from said housing to permit insertion of a tool into the interior of said housing, =link break means including a transverse pin on said door and a cam pivotally mounted on said door and engaging said fuse link and having a tool engaging surface spaced from said pin and from its point of engagement with said fuse link, and tool lever means adapted to be inserted into the interior of said housing for actuating said link break means to mechanically stress and rupture said fuse link, said lever means having a hook first portion adapted to engage said pin as a fulcrum and a second portion adapted to engage said surface of said cam when said hook portion is fulcrumed on said pin.

6. A housed fuse cutout comprising, in combination, a housing, first and second electrical terminals within said housing, closure means for said housing pivotally mounted thereon, fuse means mounted on said closure means including a fuse tube movable relative to said closure means and biased toward a drop-out position wherein it is visible from the exterior of said housing and a mechanically rupturable fuse link within said fuse tube, means for normally holding said fuse tube in -an operative position within said housing wherein said fuse means electrically bridges said first and second terminals when said closure means is in closed position and being responsive to rupture of said fuse link to release said fuse tube and permit movement thereof to said drop-out position, a portion of said closure means being spaced from said housing to permit insertion of a tool into the interior of said housing, and means within said housing for rupturing said fuse link, said link rupturing means including fulerum means within said housing mounted on said closure means, said link rupturing means engaging said fuse link and having a surface adapted to engage the portion of said tool in 6 serted within said housing when it is pivoted on said fulcrum means to permit imparting of a force by said tool to said link rupturing means through lever action.

7. A housed fuse cutout comprising, in combination, a housing, upper and lower stationary contacts within said housing, a door pivotally mounted on said housing, a fuse tube mounted on said door having an upper contact and a lower contact respectively engaging the upper and lower stationary contacts and having an open lower end, a mechanically rupturable fuse link within said fuse tube electrically joining the upper and lower contacts of the fuse tube and projecting outwardly from the lower end of said fuse tube, a portion of said door being spaced from said housing to permit insertion of a tool into the interior of said housing, a flipout lever pivotally mounted on said door and engaging said fuse link, said lever being spring biased toward Hip-out motion to withdraw any remaining portion of said fuse link from said fuse tube upon rupture of said fuse link and being restrained against flipout motion by said fuse link, and fuse link rupturing means including fulcrum means on said door and a tool engaging surface on said fiipout lever spaced from said fulcrum means and also so spaced from the point of engagement of said flipout lever with said fuse link that a force exerted against said surface urges said flipout lever toward flipout motion, thereby permitting rupture of said fuse link by said tool inserted within said housing and used as a -lever while bearing against said surface and pivoted about said fulcrum means.

8. A housed fuse cutout having indicating means for showing rupture of a fuse link comprising, in combination, a housing, first and second electrical terminals within said housing, a door pivotally mounted on said housing, fuse means mounted on said door for electrically bridging said first and second terminals including a fuse tube movable relative to said door and biased toward a drop-out position wherein it is visible from the exterior of said housing and a mechanically rupturable fuse link within said fuse tube, a portion of said door being spaced from said housing to permit insertion of a tool into the interior of said housing, a flipout lever pivotally mounted on said door and engaging said fuse link and spring-biased toward flipout motion and arranged to withdraw any portion of said fuse link from said fuse tube upon rupture of said fuse link, and link break means including fulcrum means mounted on said door and a tool engaging surface on said flipout lever spaced from said fulcrum means and also so spaced from the point of engagement of said flipout lever with said fuse link that a force exerted against said surface urges said lever toward flipout motion in a direction to break said fuse link, whereby said fuse link may be mechanically ruptured by said tool inserted within said housing and used as ya lever bearing against said surface and pivoted about said fulcrum means, means normally holding said fuse tube in an operative position wherein said fuse means electrically bridges said first and second terminals and being responsive to ipout motion of said lever to release said fuse tube and permit movement thereof to said drop` out position, said last-named means providing a time delay between rupture of said fuse link and release of said fuse tube and assuring complete clearing of the fuse tube before it is released for drop-out motion 'and thus preventing arcing at said first and second terminals.

References Cited in the file of this patent UNITED STATES PATENTS 2,458,743 Schultz Jan. 1l, 1949 2,672,539 Steinmayer Mar. 16, 1954 2,820,868 McCloud Jan. 2l, 1958 2,829,218 Harder Apr. l, 1958 2,835,764 Earle May 20, 1958 2,836,681 Bracey May 27, 1958 Y2,843,704 Wood July 15, 1958 

